Underland 4

Victor Renquist, centuries-old master of a small colony of Nosferatu, has been "recruited"-forcibly-by an undercover branch of the National Security Agency, Paranormal Operations and Research. They need his help. It seems that certain members of Hitler's Third Reich escaped to a secret world below Antarctica, taking with them some very advanced technology. Human teams have failed to infiltrate the base, and Renquist is the NSA's last chance.
The team is small: Renquist; his right-hand man, Lupo; an extremely unorthodox hardline NSA operative named Jack Coulson; and Thyme Bridewell, a failed NSA brain-control experiment originally intended as Renquist's lunch. What they find in Underland taxes even Renquist's supernormal powers. The quondam Nazis have some very powerful allies — the Dhrakuh, a race of sentient reptiles from the dawn of time. Their goal is nothing less than the conquest of the entire world.
To make matters worse, Renquist is hampered by...